The present invention relates to a roll-blind.
In general, a roll-blind is so constructed that it is opened or closed by winding up a blind cloth onto a winding roll or unwinding the blind cloth from the winding roll.
Heretofore, the roll-blind employs a coil spring which is contained in the winding roll to continuously apply elastic force to said winding roll to rotate it in the cloth winding-up direction. In such a roll-blind in which the blind cloth is subjected to the action of the elastic force of the coil spring, it is very difficult to stop the blind cloth at a desired lowered position against the action of the coil spring and the adjustment of the elastic force of the coil spring has significant bearing on the operation of the roll-blind.
For example, if the elastic force of the coil spring is excessively strong, the blind cloth is wound up suddenly, so that the blind cloth cannot be regularly wound up onto the winding roll and in some circumstances the blind cloth may become damaged. On the other hand, if the elastic force of the coil spring is excessively small, the blind cloth cannot be fully wound up onto the winding roll, that is, the complete operation of blind cannot be assured.